Language Workbenches

Hip Tree Editors

Isomorf with online demo ([HN][hn:isomorph]). First
impressions: great discoverability (entered a switch statement
without knowing its syntax); annoying to scroll with arrow keys
(inorder navigation); surprisingly difficult to enter numbers; my
fibonacci function failed with an “unevaluatable” error; slow
(sometimes had a half-second delay after keypress, or to fill an
autocomplete box).